D.c. vibrating horn

ABSTRACT

A D.C. horn apparatus has been provided including an open housing, a diaphragm mounted over the opening in the housing and an electromagnetic means including a circuit breaker contact for providing vibrating motion to the diaphragm when energized. The improvement includes a resilient vibrating contact mounted at one end to the housing having one contact thereon, a secondary contact arm mounted on the housing at one end and having a second contact engaging said first contact for closing the circuit of the electromagnetic means, and a resilient damper pad mounted on the free end of the vibrating arm for engaging the diaphragm and transferring motion of the diaphragm when activated by said electromagnetic means for opening the contacts and damping interaction of the vibrating arm and the diaphragm.

United States Patent Berns [54] D.C. VIBRATING HORN [72] Inventor:Charles Berns, Brookfield, Conn.

[73] Assignee: Edwards Company, Inc., Norwalk, Conn.

[22] Filed: July 10, 1970 21 Appl. No.: 53,754

1151 3,656,156 1451 Apr. 11, 1972 FOREIGN PATENTS OR APPLICATIONS511,295 10/1930 Germany ..340/403 Primary Examiner-Thomas B. HabeckerAttorneyHarold S. Wynn and John P. De Luca [5 7] ABSTRACT A D.C. hornapparatus has been provided including an open housing, a diaphragmmounted over the opening in the housing and an electromagnetic meansincluding a circuit breaker contact for providing vibrating motion tothe diaphragm when energized. The improvement includes a resilientvibrating contact mounted at one end to the housing having one contactthereon, a secondary contact arm mounted on the housing at one end andhaving a second contact engaging said first contact for closing thecircuit of the electromagnetic means, and a resilient damper pad mountedon the free end of the vibrating arm for engaging the diaphragm andtransferring motion of the diaphragm when activated by saidelectromagnetic means for opening the contacts and damping interactionof the vibrating arm and the diaphragm.

2 Claims, 3 Drawing Figures PATENTEDAPR 1 1 912 FIG. 2

FIG. 1

D.C. VIBRATING HORN BACKGROUND OF INVENTION This invention relates tosound producing devices and in particular to a direct current actuatedvibratory horn.

In the construction of fire alarm or intrusion warning systems forfactories, schools or hospitals it is necessary to provide numerousaudible warning devices in and about the structure. In general, thesedevices for providing audible alarm are uniformly constructed and arereadily interchangeable at any of the warning locations. Generally,these devices are mass produced items and as such must be efficient inoperation, simple in construction and economical in terms ofmanufacturing costs.

Generally in the construction of a D.C. bell or born there is anecessity for providing a device, for interrupting periodically the dutycycle of a driver means or that which actuates the sound producingdiaphragm or bell clapper. Such an apparatus is generally a set ofcontacts in the energizing circuit of the driving means periodicallyactuated to an open condition for deenergizing the driving means andreleasing the diaphragm or noise producing mechanism of the device. Sucha mechanical arrangement must be capable of efficient operation and mustalso be durable to operate over many thousands of cycles. Vibratorycharacteristics of the diaphragm and the contact apparatus must beconsidered for the most efficient operating characteristics.

It is therefore an object of the present invention to provide anarrangement which substantially obviates one or more of the limitationsand disadvantages of the prior arrangements.

It is another object of the present invention to provide a simplifiedaudible D.C. horn.

It is another object of the present invention to provide a warningapparatus of moderate cost.

SUMMARY OF INVENTION There has been provided an electric horn includingan open housing, a diaphragm mounted over the opening in the housing andan electromagnetic means including a circuit breaker contact forproviding vibrating motion to said diaphragm when energized. Theimproved circuit breaker contact comprises; a resilient vibratingcontact arm mounted at one end to the housing and having one contactthereon, a secondary contact mounted to the housing at one end andhaving a second contact thereon engaging said first contact for closingthe circuit of the electromagnetic means, and a resilient damper padmounted at the free end of the vibrating arm for engaging the diaphragmand transferring motion of the diaphragm when ac tivated by theelectromagnetic means for opening the contacts and damping interactionof the vibrating horn and the diaphragm.

For a better understanding of the present invention, together with otherand further objects thereof, reference is had to the followingdescription taken in connection with the accompanying drawings, whileits scope will be pointed out in the appended claims.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a partially rear elevation ofthe DC. hornv described in the present application.

FIG. 2 is a side section elevation of FIG. 1 along line 2-2. FIG. 3 is adetailed illustration of the contact assembly of the present inventionalong line 3-3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS about the coil 13forconcentrating the magnetic field produced in the coil 13 whenenergized. An armature 16 mounted to the diaphragm 11 engaging theforward ends of the laminations 15 completes a magnetic circuit for thedriving means 12. Each time the electromagnetic driving means 12 isenergized, it draws the armature 16 towards the laminations andconsequently moves the diaphragm 11. When the electromagnet 12 isdeenergized, the resiliency of the diaphragm urges the armature awayfrom the laminations l5 and produces a vibratory sound.

The contact mechanism shown in FIG. 3 is responsive to the motion of thediaphragm 11 drawn by the electromagnet 12. The contacts 16 complete acircuit for energizing the coil 13. Each time the diaphragm 11 is drawntowards the electromagnet 12, a vibratory member 17 fixed at one end toan insulated mounting bracket 18 engages the diaphragm 11 so that thecontacts 16 open upon a sufficient motion of diaphragm 11 towards theelectromagnet 12. The open circuiting of contact 16 consequentlydeenergizes the electromagnet and releases the diaphragm. Again, uponmotion of the diaphragm 11 away from the electromagnet'lZ, the contacts16 close again and complete the circuit for energizing the electromagnetl2 and the cycle is repeated .until the power source is disconnectedfrom the inputs to the horn.

The horn also includes a baffiing plate 20 suitably mounted to thediaphragm for providing a resonant tone to the sound generated by thevibrating diaphragm 11. A front face plate 21 mounted over the diaphragmand the baffling plate assembly has holes therein 22 for providing apath for the generated sound and for protecting the diaphragm l1 andbaffiing plate 20 assembly. The cover plate 21 also includes a noisecontrol including a set screw 23 mounted through hole 24 in the frontplate 21. The screw 23 engages with the baffiing plate 20 as it ismoving and according to the position of the head of the screw 23relative to the baffiing plate 20 noise is suppressed. That is, if thehead of the screw 23 is relatively closely spaced with the baffiingplate 20, less sound is emitted because the throw of the diaphragm 11and bafiling plate 20 is substantially reduced.

The configuration of the contact mechanism shown in FIG. 3 has beendesigned in order to provide ease of installation, reduce costs ofcomponents and easy adjustment of the tension of the contact mechanism.The mechanism shown in FIG. 3 is mounted on an extension 25 of thebracket 14. The extension 25 is. a tab having a second extension 26thereon and a hole 27 for movable mounting by adjusting screw 28. Thecontacts 16 are mounted on the vibratory member 17 and contact arm 29respectively and are held rigidly at one end by the insulative bracketmembers 18. A spring steel member 30 mounted directly below thevibratory member 17 provides resiliency to the vibratory member 17. Thetension or the elasticity of the spring member 30 is chosen to be about10 times that of the diaphragm so that upon initial actuation of thediaphragm 11, the vibratory member 17 and the spring 30 travelingtogether are substantially at rest each time the diaphragm 11 engagesthe vibratory member 17 for opening the contacts 16. Under theseconditions, the diaphragm and vibratory arm 17 are substantiallysynchronized and a firm closure of contact 16 is maintained each timethe vibratory member returns to the rest or initial position.

Vibratory member 17 also includes a damper pad 19 fixed to its free end.The damper pad 19 is formed of resilient material, preferably nylon,which insulates the metal vibratory arm 17 from the diaphragmelectrically and also damps out secondary oscillations which might bepresent each time the diaphragm engages with the vibratory arm 17. Thisdamping action tends to make the actuation of the contacts 16 moreuniform and also suppress oscillations which would cause an undesiredtone. In addition, the resiliency of the damper pad 19 tends to protectthe diaphragm from damage by the constant mating of the vibratory member17 and diaphragm l1.

Adjustment of the tension on the vibratory member 17 against the contactarm 29 is accomplished by the adjustment of the position of set screw28. Set screw 28 engages with the lower tab 26. Disposed between thebracket 18 and the tab 26 is a spring 31 used to keep tension againstthe set screw to maintain its position. As the set screw 28 is turned intowards the diaphragm, bracket 18 upon which the contact arm 29 andvibratory member 17 are mounted, moves towards the diaphragm also. Whenthe damper pad 19 engages with the diaphragm as the screw 28 is turnedin, the contacts 16 tend to separate. Any vibration at all of thediaphragm therefore would also immediately disconnect the contact 16 andcause the armature to be released. If, however, it is desired to adjustthe frequency of the diaphragm, the set screw 28 may be backed off untila substantial throw of the diaphragm causes a separation of the contacts16. Actually, the farther the diaphragm must move to actuate thecontacts, the lower the frequency of the horn will ultimately be. Thisfeature adds versatility to the horn by permitting frequency variationsin the tone of the horn output while providing a rather simple means foradjusting the tone quality of the device.

A capacitor 32, mounted adjacent to the assembly, is connected acrossthe contact points 16 as shown and absorbs energy for suppressing thespark across the contacts 16 when they are opened by the influence ofthe diaphragm 11 against damper pad 19. Energy stored in the coil 13tends to are across the contacts 16 when they are opened and thecapacitor 32 absorbs this energy thus reducing any spark which mightoccur. Spark suppression serves two purposes; one of which is reductionin the wear of the contact points 16 caused by the constant arcing andalso in certain areas, spark suppression is a requirement in respect totire control regulations.

While there has been shown what is at present believed to be thepreferred embodiment of the present invention, it will be obvious tothose skilled in the art that various changes and modifications may bemade without departing from the true spirit and scope of the invention,and it is therefore aimed in the appended claims to cover all suchchanges and modifications that fall within the true spirit and scope ofthe invention.

What is claimed is:

1. An electric horn including an open housing, a diaphragm securedbetween at least one peripheral support and the housing over the openingin the housing and an electromagnet operating means including a circuitbreaker for providing vibrating motion to the diaphragm when energizedwith direct current wherein the improvement comprises;

a. a circuit breaker supporting bracket formed integral with theperipheral support and having one leg extending inwardly over thediaphragm with a single opening formed therein for reception of amounting and adjustment screw;

nection terminals extending laterally therefrom,

. the vibrating contact having a vibrating arm carrying a contact pointextending parallel to the diaphragm and an actuating arm extendingnormal to the diaphragm and having a plastic tip disposed on the endthereof to be periodically contacted directly by a portion of thediaphragm upon operation of the horn, the vibrating arm having a singleopening formed therein for passage of a mounting and adjustment screw,

2. the fixed contact having a contact point at one end for cooperatingwith the contact point of the vibrating contact and having a singleopening at the other end for passage of a mounting and adjustment screw,

0. a plurality of spacers of insulating material for aligning,supporting and insulating the vibrating and fixed contacts one above theother, the spacers having a flat surface adjoining another leg of thesupporting bracket to prevent rotation of the spacers and contacts andhaving a single central opening for an adjustment and mounting screw,and

. mounting and adjusting means for securing the contacts and the spacersto said one leg of the mounting bracket including,

1. a screw passing through the openings in the spacers and the contactsand threaded into the opening in said one leg of the bracket foradjustably mounting the contacts on the bracket, and v 2. a relativelystiff compressed spring disposed between the spacers and said one leg ofthe bracket for permitting adjustment of the spacing of the vibratingcontact relative to the diaphragm upon turning the mounting andadjustment screw but maintaining the contacts firmly secured between thespacers.

2. An electric horn according to claim 1 wherein the plastic tip isformed of nylon and has a substantially broad flat surface forcontacting the diaphragm.

. cooperating vibrating and fixed contacts having wire con-'

1. An electric horn including an open housing, a diaphragm securedbetween at least one peripheral support and the housing over the openingin the housing and an electromagnet operating means including a circuitbreaker for providing vibrating motion to the diaphragm when energizedwith direct current wherein the improvement comprises; a. a circuitbreaker supporting bracket formed integral with the peripheral supportand having one leg extending inwardly over the diaphragm with a singleopening formed therein for reception of a mounting and adjUstment screw;b. cooperating vibrating and fixed contacts having wire connectionterminals extending laterally therefrom,
 1. the vibrating contact havinga vibrating arm carrying a contact point extending parallel to thediaphragm and an actuating arm extending normal to the diaphragm andhaving a plastic tip disposed on the end thereof to be periodicallycontacted directly by a portion of the diaphragm upon operation of thehorn, the vibrating arm having a single opening formed therein forpassage of a mounting and adjustment screw,
 2. the fixed contact havinga contact point at one end for cooperating with the contact point of thevibrating contact and having a single opening at the other end forpassage of a mounting and adjustment screw, c. a plurality of spacers ofinsulating material for aligning, supporting and insulating thevibrating and fixed contacts one above the other, the spacers having aflat surface adjoining another leg of the supporting bracket to preventrotation of the spacers and contacts and having a single central openingfor an adjustment and mounting screw, and d. mounting and adjustingmeans for securing the contacts and the spacers to said one leg of themounting bracket including,
 1. a screw passing through the openings inthe spacers and the contacts and threaded into the opening in said oneleg of the bracket for adjustably mounting the contacts on the bracket,and
 2. a relatively stiff compressed spring disposed between the spacersand said one leg of the bracket for permitting adjustment of the spacingof the vibrating contact relative to the diaphragm upon turning themounting and adjustment screw but maintaining the contacts firmlysecured between the spacers.
 2. the fixed contact having a contact pointat one end for cooperating with the contact point of the vibratingcontact and having a single opening at the other end for passage of amounting and adjustment screw, c. a plurality of spacers of insulatingmaterial for aligning, supporting and insulating the vibrating and fixedcontacts one above the other, the spacers having a flat surfaceadjoining another leg of the supporting bracket to prevent rotation ofthe spacers and contacts and having a single central opening for anadjustment and mounting screw, and d. mounting and adjusting means forsecuring the contacts and the spacers to said one leg of the mountingbracket including,
 2. a relatively stiff compressed spring disposedbetween the spacers and said one leg of the bracket for permittingadjustment of the spacing of the vibrating contact relative to thediaphragm upon turning the mounting and adjustment screw but maintainingthe contacts firmly secured between the spacers.
 2. An electric hornaccording to claim 1 wherein the plastic tip is formed of nylon and hasa substantially broad flat surface for contacting the diaphragm.